Not sure if the MOTD's use the same Web Browser as Steam (Probably).. But
But Steam just updated their web browser yesterday (5/4/2016).
Maybe this is causing an issue?Updated the web browser component to Chromium version 49.0.2623.110

In your steam library, Right click on CS:S, Click properties, hit "set launch options"
Without the quotations, Type "-dxlevel -110" and press apply the setting
Launch up into CS:S, Be sure to go into the options and set your video settings back to what they were.

In your steam library, Right click on CS:S, Click properties, hit "set launch options"
Without the quotations, Type "-dxlevel -110" and press apply the setting
Launch up into CS:S, Be sure to go into the options and set your video settings back to what they were.